In the manufacture of metal cans and other containers by draw-redraw and drawing and ironing techniques, the container body or shell is formed, with an irregular or uneven edge, which must be removed prior to assembly with the end closure. The trimming apparatus presently employed leaves a sharp burr projecting either inwardly or outwardly of the body, which burr tends to cause jamming and damage to equipment, and interferes with forming apparatus, leading to crack development and ultimate container failure. While machinery for burr removal is available, as exemplified by that shown in U.S. Pat. No 3,581,691, so far as is known none of the existing equipment deals with the removal of internal burrs in an entirely satisfactory and sufficiently simple manner.
Accordingly, it is an object of the present invention to provide a novel method and apparatus for trimming cylindrical metal bodies, and for removing internal burrs which result from the trimming operation.
It is also an object of the invention to provide such a method and apparatus which are simple, efficient and convenient, and are adapted to economical, high-speed operation.
A more specific object is to provide such a method and apparatus which are particularly adapted for the production of container shells by draw-redraw and drawing and ironing techniques and, in particular, for producing such shells from steel and aluminum blanks.